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1 – 10 of 220Gary Hunter, Randy Vander Wal, Laura Evans, Jennifer Xu, Gordon Berger, Michael Kullis and Azlin Biaggi‐Labiosa
The development of chemical sensors based on nanostructures, such as nanotubes or nanowires, depends on the capability to reproducibly control the processing of the sensor…
Abstract
Purpose
The development of chemical sensors based on nanostructures, such as nanotubes or nanowires, depends on the capability to reproducibly control the processing of the sensor. Alignment and consistent electrical contact of nanostructures on a microsensor platform is challenging. This can be accomplished using labor‐intensive approaches, specialized processing technology, or growth of nanostructures in situ. However, the use of standard microfabrication techniques for fabricating nanostructured microsensors is problematic. The purpose of this paper is to address this challenge using standard photoresist processing combined with dielectrophoresis.
Design/methodology/approach
Nanostructures are suspended in photoresist and aligned between opposing sawtooth electrode patterns using an alternating current (AC) electric field (dielectrophoresis). The use of photoresist processing techniques allow the burying of the nanostructures between layers of metal, thus improving the electrical contact of the nanostructures to the microsensor platform.
Findings
This approach is demonstrated for both multi‐walled carbon nanotubes and tin oxide nanowires. Preliminary data show the electrical continuity of the sensor structure as well as the response to various gases.
Research limitations/implications
It is concluded that this approach demonstrates a foundation for a new tool for the fabrication of microsensors using nanostructures, and can be expanded towards enabling the combination of common microfabrication techniques with nanostructured sensor development.
Originality/value
This approach is intended to address the significant barriers of deposition control, contact robustness, and simplified processing to realizing the potential of nanotechnology as applied to sensors.
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José Miguel Monzón-Verona, Santiago Garcia-Alonso, Javier Sosa and Juan A. Montiel-Nelson
The purpose of this paper is to explain in detail the optimization of the sensitivity versus the power consumption of a pressure microsensor using multi-objective genetic…
Abstract
Purpose
The purpose of this paper is to explain in detail the optimization of the sensitivity versus the power consumption of a pressure microsensor using multi-objective genetic algorithms.
Design/methodology/approach
The tradeoff between sensitivity and power consumption is analyzed and the Pareto frontier is identified by using NSGA-II, AMGA-II and ɛ-MOEA methods.
Findings
Comparison results demonstrate that NSGA-II provides optimal solutions over the entire design space for spread metric analysis, and AMGA-II is better for convergence metric analysis.
Originality/value
This paper provides a new multiobjective optimization tool for the designers of low power pressure microsensors.
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Reviews intelligent structures through surface‐ and bulk‐micromachining. Examines the merits of these techniques and their past, present and future applications to real‐life…
Abstract
Reviews intelligent structures through surface‐ and bulk‐micromachining. Examines the merits of these techniques and their past, present and future applications to real‐life problems.
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The “thermodynamic model” constitutes a unified theoretical framework for the coupled simulation of carrier and energy flow in semiconductor devices under general ambient…
Abstract
The “thermodynamic model” constitutes a unified theoretical framework for the coupled simulation of carrier and energy flow in semiconductor devices under general ambient conditions such as, e.g., the presence of a quasi‐static magnetic field or the interaction with an electromagnetic radiation field (light). The current relations governing particle and heat transport are derived from the principles of irreversible phenomenological thermodynamics; the driving forces include drift, diffusion, thermal diffusion, and deflection by the Lorentz force. All transport coefficients may be interpreted in terms of well‐known thermodynamic effects and, hence, can be obtained from theoretical calculations as well as directly from experimental data. The thermodynamic model allows the consistent treatment of a wide variety of physical phenomena which are relevant for both the operation of electronic devices (e.g., lattice heating, hot carrier and low temperature effects) and the function of microsensors and actuators (e.g., thermoelectricity, galvanomagnetism and thermomagnetism).
Lukas Fujcik, Roman Prokop, Jan Prasek, Jaromir Hubalek and Radimir Vrba
The purpose of this paper is to design and create a potentiostat that can be integrated and encapsulated within a microelectrode as a low‐cost electrochemical sensor. Recently…
Abstract
Purpose
The purpose of this paper is to design and create a potentiostat that can be integrated and encapsulated within a microelectrode as a low‐cost electrochemical sensor. Recently, microsystems on sensors or lab on a chip using electrochemical detection of substances matters are pushing forward into the area of analysis. For providing electrochemical analysis, the microsystem has to be equipped with an integrated potentiostat.
Design/methodology/approach
The integrated potentiostat with four current ranges (from 1 μA to 1 mA) was designed in the CADENCE software environment using the AMIS CMOS 0.7 μm technology and fabricated under the Europractice program. Memory cells of 48 bytes are implemented with the potentiostat using VERILOG.
Findings
The characteristics of integrated potentiostat are strictly linear; the measured results confirm the simulated values. The potentiostat measurements error is about 1.5 percent and very low offsets are reached by the offset‐zeroing circuitry.
Research limitations/implications
The detection limit of the current at the lowest range with respect to S/N ratio is about 10 nA.
Practical implications
The integrated potentiostat is embedded on a screen‐printed sensor and its characteristics are successfully verified. Lower range of 100 nA can be implemented on a new microchip as well as rail‐to‐rail output circuitry would increase the voltage dynamic range.
Originality/value
The integrated potentiostat with very good parameters is designed for a wide spectrum of electrochemical applications such as lab on a chip, embedded electrochemical systems, etc. The integrated system enables storing of information about the system measured, for instance, calibration and fabrication data of the electrochemical sensor.
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Amin TermehYousefi, Samira Bagheri and Nahrizul Adib
Biotechnology is closely associated to microfluidics. During the last decade, designs of microfluidic devices such as geometries and scales have been modified and improved…
Abstract
Purpose
Biotechnology is closely associated to microfluidics. During the last decade, designs of microfluidic devices such as geometries and scales have been modified and improved according to the applications for better performance. Numerous sensor technologies existing in the industry has potential use for clinical applications. Fabrication techniques of microfluidics initially rooted from the electromechanical systems (EMS) technology.
Design/methodology/approach
In this review, we emphasized on the most available manufacture approaches to fabricate microchannels, their applications and the properties which make them unique components in biological studies.
Findings
Major fundamental and technological advances demonstrate the enhancing of capabilities and improving the reliability of biosensors based on microfluidic. Several researchers have been reported verity of methods to fabricate different devices based on EMS technology due to the electroconductivity properties and their small size of them. Therefore, controlled fabrication method of MEMS plays an important role to design and fabricate a highly selective detection of medical devices in a variety of biological fluids. Stable, tight and reliable monitoring devices for biological components still remains a massive challenge and several studies focused on MEMS to fabricate simple and easy monitoring devices.
Originality/value
This paper is not submitted or under review in any other journal.
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